Trinitarians cannot reconcile this verse, because according to them the Father, Son, and Holy Spirit are God together, while this verse specifies the Father alone as being God who is above all. You shouldn't force the scripture to fit your doctrine, you should force your doctrine to fit the scripture. the bible doesn't teach a trinity, it also does not teach Unitarianism. All this confusion comes from the modern word "God", let me explain.
If we look up the modern english definition of God, this is what we get:
Merriam-Webster Definition of god: 1 capitalized : the supreme or
ultimate reality: such as a : the Being perfect in power, wisdom, and
goodness who is worshipped as creator and ruler of the universe b
Christian Science : the incorporeal divine Principle ruling over all
as eternal Spirit : infinite Mind
Dictionary.com Definition of god: noun
1. the one Supreme Being, the creator and ruler of the universe.
2. the Supreme Being considered with reference to a particular attribute: the God of Islam.
3. (lowercase) one of several deities, especially a male deity, presiding over some portion of worldly affairs.
This is what we have been programed to think when we hear the word God, but it is actually a completely different word and definiton from the ancient title אֱלֹהִים (Alahym/ Elohim) which is used in the Old testament scriptures.
WHen we look at the Strongs concordance defintion of Alahym we get something different than the modern definiton:
Strongs Hebrew #430
1 plural in number.
a. rulers, judges, either as divine representatives at sacred places
or as reflecting divine majesty and power: האלהים Exodus 21:6 (Onk ᵑ6,
but τὸ κριτήριον τοῦ Θεοῦ ᵐ5) Exodus 22:7; Exodus 22:8; אלהים Exodus
22:8; Exodus 22:27 (ᵑ7 Ra AE Ew RVm; but gods, ᵐ5 Josephus Philo AV;
God, Di RV; all Covt. code of E) compare 1 Samuel 2:25 see Dr.; Judges
5:8 (Ew, but gods ᵐ5; God ᵑ6 BarHebr.; יהוה ᵑ9 Be) Psalm 82:1; Psalm
82:6 (De Ew Pe; but angels Bl Hup) Psalm 138:1 (ᵑ6 ᵑ7 Rab Ki De; but
angels ᵐ5 Calv; God, Ew; gods, Hup Pe Che).
b. divine ones, superhuman beings including God and angels Psalm 8:6
(De Che Br; but angels ᵐ5 ᵑ6 ᵑ7 Ew; God, RV and most moderns) Genesis
1:27 (if with Philo ᵑ7 Jerome De Che we interpret נעשה as God's
consultation with angels; compare Job 38:7).
c. angels Psalm Job 97:7 (ᵐ5 ᵑ6 Calv; but gods, Hup De Pe Che);
compare בני (ה)אלהים = (the) sons of God, or sons of gods = angels Job
1:6; Job 2:1; Job 38:7; Genesis 6:2,4 (J; so ᵐ5 Books of Enoch &
Jubilees Philo Jude Jude 1:6 2Peter 2:4 JosAnt. i. 3. 1, most ancient
fathers and modern critics; against usage are sons of princes, mighty
men, Onk and Rab.; sons of God, the pious, Theod Chrys Jerome
Augustine Luther Calv Hengst; ᵐ5L read οἱ υιὁὶ τοῦ Θεοῦ), compare בני
אלים.
The orginal title Alahym does not mean "one supreme being who created all things", not even close.
Alahym is a title of divine authority given to the Most High. It is a title also given to angels and high men of authority to judge in Israel. And last, but certainly not least, it is a title given to the Son by the Father Himself.
Examples of times Alahym is used for men of authority in Israel:
Exodus 21:6 (KJV) "Then his master shall bring him unto the
judges(אֱלֹהִים= Alahym); he shall also bring him to the door, or unto the door post; and his master shall bore his ear through with an
aul; and he shall serve him for ever.
Exodus 22:8-9 (KJV) "8 If the thief be not found, then the master of
the house shall be brought unto the judges, to see whether he have put
his hand unto his neighbour's goods. 9 For all manner of trespass,
whether it be for ox, for ass, for sheep, for raiment, or for any
manner of lost thing which another challengeth to be his, the cause of
both parties shall come before the judges(אֱלֹהִים= Alahym); and
whom the judges shall condemn, he shall pay double unto his neighbour.
1 Samuel 2:25 " If one man sin against another, the
judge(אֱלֹהִים= Alahym) shall judge him: but if a man sin against the LORD, who shall intreat for him? Notwithstanding they hearkened
not unto the voice of their father, because the LORD would slay them.
Psalm 82:6 " I have said, Ye are gods(אֱלֹהִים= Alahym) ; and all
of you are children of the most High. ( This one was quoted by Yahuwshuwa ( Jesus) in John 10:34 and he directed it toward the jews)
Example of Alahym used for angels:
Psalm 8:5 "For thou hast made him a little lower than the angels
(אֱלֹהִים= Alahym), and hast crowned him with glory and honour.
Alahym means ruler and judge reflecting divine majesty and authority. It means mighty one, its transalted as mighty one in the KJV. It was a title given to men in the position of authority in Israel to rule and judge the Most High's people according to his divine law. To be representatives of Yahuwah (YHWH). It was given to angels because of their divine authourty to work the Father's will with mankind.
If even sinful men were given the title Alahym because of their authority to rule, judge, and represent divine authority, how much more does the Son Yahuwshuwa HaMashiyach fulfill this title, being King of king and judge of the world, the very definition of the title. Being the ultimate representative, He is the very Word and image of the Father, that has been given all authority in heaven and earth.
In psalm 45, a prophecy of the Messiah, we see the Father calling the Son Alahym:
Psalm 45:5-6 " 6 Thy throne, O God, is for ever and ever: the
sceptre of thy kingdom is a right sceptre.
7 Thou lovest righteousness, and hatest wickedness: therefore God, thy
God, hath anointed thee with the oil of gladness above thy fellows.
So we see here the Father being Alahym, while he also calls his Son Alahym. Yahuwshuwa calls His Father "the only true God" (John 17:3) because His Father is Ruler over all and above all, the one who gives authority. The Son even said the Father is greater than I am, and that the Son can do nothing without the Father, and that he learned all things from the Father.
The scriptures does not teach a trinity, the Apostle John taught in the beginning was the Word with the Father, and the Word was Alahym with the Father. The Father created all things through His Word/Son. They are two, but one in spirit and will. The Holy Spirit is not a third person of a trinity ( a word not even in the bible), the Spirit is the very power,life, will, essence, and breathe of Alahym sent forth performing His will.
So now that we have the correct understanding of the title Alahym, we can properly interpret Pauls words. lets put 1 Corinthians 8 in context:
1 Corinthians 8:4-7
As concerning therefore the eating of those things that are offered
in sacrifice unto idols, we know that an idol is nothing in the world,
and that there is none other God but one.
5 For though there be that are called gods, whether in heaven or in
earth, (as there be gods many, and lords many,)
6 But to us there is but one God, the Father, of whom are all things,
and we in him; and one Lord Jesus Christ, by whom are all things, and
we by him.
7 Howbeit there is not in every man that knowledge: for some with
conscience of the idol unto this hour eat it as a thing offered unto
an idol; and their conscience being weak is defiled.
So Paul is speaking about eating meats offered to idol, and how the gentiles worship many gods and lords. This is a reference to the Old testament where the gentiles worshiped false alahym and baalim (lords). So Paul then connects that to saying there is only one Alahym and one Lord. When he says there is "one Lord" is he saying the Son is the only one with the title Lord? No, i can show you hundreds of verses where the Father and other respected men of Israel are called Lord. When it says there " is one God" is it saying that no one else has that title? no, i already proved others were given that title.
What Paul is doing is showing the Hierarchy, showing the Father is ruler and above all, who has anointed his Son to be Lord of all creation. The Son follows the will of the Father, not the other way around.